Dimethine merocyanine dyes



Patented Jan. 10, 1950 DIMETHINE MEROCYANINE DYES Leslie G. S. Brooker and Frank L. White, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New 7,

Jersey N0 Drawing. Application June 23, 1945,

Serial No. 601,332

This invention relates to dimethine merocyanine dyes and to a process for the preparation thereof. This application is a continuation-inpart of our copending application Serial No. 519,354, filed January 22, 1944 (now United States Patent 2,478,366, dated August 9, 1949).

Dimethine merocyanine (merocarbocyanine) dyes containing an alkyl group on the dimethine.

chain are known (see United States Patent 2,263,757, dated November 25, 1941). In these known dimethine merocyanine dyes, the alkyl group is on the methine group adjacent to the keto nucleus as shown in the following general formula:

wherein R, and R represent alkyl groups, Y represents the non-metallic atoms necessary to complete a benzothiazole, a benzoselenazole, a naph-' thothiazole nucleus, etc., and Z represents the non-metallic atoms necessary" to complete a 5-membered or 6-membered heterocyclic nucleus, e. g. a rhodanine nucleus, a 2-thio-2,4(3,5)- oxazoledione nucleus or a thiobarbituric acid nucleus.

We have now found dimethine merocyanine dyes containing an alkoxyl or an aryloxyl group on the dimethine chain, the alkoxyl or aryloxyl group being on the methine group removed from the keto nucleus rather than on the .methine group adjacent to the keto nucleus. We have further found that these new .dyes sensitize photographic silver halide emulsions.

17 Claims. (Cl. 260-240) I of the a-naphthothiazole series, those of the It is, accordingly, an object of our invention to wherein R represents an alkyl group of the formula CnH2n+l wherein n represents a positive integer, R1 represents a member selected from the group consisting of alkyl groups, aryl groups of the benzene series and aryl groups of the naphthalene series, Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from those consisting of those of the benzoxazole series, those of the benzothiazole series; those of the benzoselenazolesriesgthosfi fi-naphthothiazole, those of the a-naphthoxazole series and those of the B-naphthoxazole series, and Q represents the non-metallic'atoms necessary to complete a heterocyclic nucleus selected from those consisting of those of the rhodanine series (e. g. rhodanine, 3-alkylrhodanines or 3-phenylrhodanines) and those of the 2-thio- 2,4(3,5) -oxazoledione series (e. g. 3-alkyl- 2,4( 3,5) -oxazolediones) Of thedyes formulated, above, those in which R represents an alkyl group of the formula CnH2n+1 wherein n represents a positive integer of from 1 to 2 sensitize photoraphic emulsions strongly.

In accordance with our invention, we prepare our new dimethine merocyanine dyes by con- (lensing a cyclammonium quaternary salt selected, from those consisting of those of the benzoxazole series, those of the benzothiazole series, those of the benzoselenazole series, those of the a-naphthoxazole series, those of the ,B-naphthoxazole series, those of the u-naphthothiazole series and those of the fi-naphthothiazole series containing in the oz-POSltiOll to the quaternary nitrogen atom av group selected from the group consisting of alkoxymethyl groups, aryloxymethyl groups of the benzene series and aryloxymethyl groups of the naphthalene series, with a' heterocyclic com pound of thefollowing general formula:

wherein Ac represents an acyl group and R2 represents an aryl group and Q has the value given above. The condensations are advantageously carried out in the presence of a basic condensing agent. An alcoholic solution of a trialkylamine, e. g. triethylamine, or a N-alkylpiperidine, e. g. N-methylpiperidine, is advantageously employed as basic condensing agent. Heat accelerates the condensations.

Our new dimethine merocyanine dyes can also be prepared by condensing a cyclammonium' quaternary salt selected from those consisting of those of the benzoxazole series, those of the benzothiazole series, those of the benzoselenazole series, those of the a-naphthoxazole series, those of the s-naphthoxazole series, those of the a-naphthothiazole series and those of the 18-naphthothiazole series, containing in the a-position to the quaternary nitrogen atom, a ,s -arylamino-a-alkoxyor a-aryloxyvinyl group, with a heterocyclic compound containing a ketoethylamine) or a N-alkylpiperidine (e. g. N- methylpiperidine) is advantageously employed as basic condensing agent.

Heat accelerates the condensations.

The following examples willzserve to illustrate our new dimethine merocyanine dyes sand the manner of obtaining the same.

Example 1.3 ethyl 5 [(3 --'methyl 2L3);-

benzothiazolylidene) 6 phenomyethylidene] rhodanine .O=CN 02H, sic-011:3: c==s .2;3.g...( 1 mol.) of 21-J(e-acetanilidora-phenoxyvinyl) -.b,enzothiazole methiodide, 0.7 g. (1 mol.) of .3.-,ethylrhodanine 110 cc. of ethyl alcohol and A6 ,g.. 1 mol.;+- per cent excess) of triethyl.- amine were heated atthe refluxingtemperature tor minutes. The coolreddish mixture was decomposition, and sensitizedga photographic ge- I latino-silver-bromogiodide emulsion towabou't 650 mu. with maximum sensitivity atabout 615 mu.

Ea:ample'2.-3 ethyl- 5 rcs methyl 21(3) beneothiazolylz'den'e) B "'(m toloazy) ethylidene] rhoclcmine I r 2.55 :g.-"(1 11101:) of IZ-lm-toloxymethyl)Ebenzothiazole'arid 1.26 g; 1mo1.) of methyl sulfate were heated together at thetemper-atureof the .steam bath for 8-hours. 'To the crude qua-ternary salt were added 3.06 g." (1111101.) oifiacetani-lido methylenerfi-ethyilrhodamine,..10: cc. :of j ethyl a1;- coholand- 1.06 .g.- (:1 lIIO1; '{-5 .cent'excess)rof triet-hylamine. This reaction mixture --was heated at {the refluxing: temperature for minutes. After-chilling at .0. (2., the solid was collected .on a funnel and washed with :ethyl alcohol. Ilhe residue was stirred; in a beaker, with hot'ethyl alcohol and afteryehilli-ng the suspension at 0 CL, the-dye waswashedon theviu-nnel with ethyl aland 33 per cent after two recrystallizations from acetone cc. per gram of dye). The minute dark red crystals with a green reflex had melting point 228-229 C. with decomposition, and sensitized a photographic gelatino-silver-bromoiodideeemulsion to. about 650 mu. with-maximum sfi i itivityrat about 615. mu;

.Ezample 3.--3 ethyl 5 [(3 methyl 2(3)- benzothz'azolylidenm ,6 (m tolorcy) ethyl- -z'deh*e'] -;2 ntliio 2,4(3,5) oxazoledione ,g.. 1(11 mol.) of ,Z-(m-tOloXymethyl)benzotliiazolandlizfigKllmol.) of methyl sulfate were heated together at. theitemperature of the steam bath fif'or 3 hours. To :the .crude quaternary salt were added 2.90 g; ,(jlmoL). of 5-.acetanilidomethylene 3 ethyl 2 thiof-' 2,l,(3,5).- oxazoledrone, 10 cc; of ethyl alcohol and 106g. (1 mol.+5 per .cent excess) of ltriethylamine. This reactionmixture was heated at the refluxing temperaturefor 20 minutes. Afterichilling the mixture at 0 0., the solid was collected on a funnel and washed with ethylalcohol- The residue was stirred, in a beaker, with hot ethyl alcohol and after chilling the suspension at 0 C., the solid was Washed on a funnel with ethyl alcohol. The yield of dye was .73-per:cent crude'and 59 per cent after two recrystallizations from ethyl alcohol (cc. 'p'er =g-rarn o'f eye); "The reddish-orange crystals with a green reflex had melting point 1959- 197 0.with'=deco1nposition, and sensitized a; wlpho'tographic gel'aitino silver 'bromo' iodide emulsion 'to' about i620 mu. with maximum sensitivity at about "580 mu. 1

-Eimmple. 4..=-..3- eth,yl .5 llta'eethylaz(3)-benzothiazolylidene)-fl-(m-toloa:y) ethylidene] ThOdCtnine CHs' 2.55 g. 1' mol.) of 2- .(m toloxymethyl) benzothiazole and 1.54 g. (1 11101.) of ethyl sulfate were heated together at 105-1 10 C. for 4 days. To the crude quaternary salt were added 3.06 g. (1 mol.) of 5 acetanilidomethylene 3 ethylrhodanine, 10 cc. of ethyl alcohol and 1.06 g. (1 mol.+5 per cent excess). .of triethylamine. This reaction mixture was heated at the refluxing temperature for 20 minutes; "The' cool mixture was stirred with 1300 -.cc.of":et h'er and after chilling at 0 0., thessol'idwa's washed'on a fu nnel'with ether. The residue :was stirred, in a beaker, with hot ethyl alcoholJand-after chilling at 0 0., the product was washed :on .a funnel with ethyl alcohol. The yield'zof :dye was 25perzc'ent crude and 17 per cent aftentwo recrystallizations from acetone (50 cc. per-:gram":nf dye).-.- The dark red crystals with .cohoL- Theyieldof dye was 67 :per -cent crude th s.agreemmezflexshad meltingpoint 210-21'1 C; with 5 decomposition, and sensitized a photographic ge latino-silver-bromo-iodide emulsion to about 650 mu. with maximum sensitivity at about 610 mu.

Example 5.3-ethyl-5- (3-ethyl-2 (3) benzothiazolylidene) ,3- (m-tolowy) ethylidene] -2-thio- 2,4 (3,5) -oa:azoledione 2.55 g. (1 mol.) of 2-(m-toloxymethyl)benzothiazole and 1.54 g. (1 mol.) of ethyl sulfate were heated together at 105-110 C. for 4 days. To the crude quaternary salt were added 2.90 g. (1 mol.) of 5-acetanilidomethylene-3-ethyl 2 thio 2,4 (3,5) -oxazoledione, 10 cc. of ethyl alcohol and 1.06 g. (1 mol.+5 percent excess) of triethylamine. This reaction mixture was heated at the refluxing temperature for 20 minutes. The cool mixture was stirred with 150 cc. of ether and after chilling at C., the solid was washed on a funnel with ether. The residue was stirred, in a beaker, with 10 cc. of hot ethyl alcohol and after chilling the suspension at 0 C., the product was washed on a funnel with ethyl alcohol. The yield of ,dye was 66 per cent crude and 46 per cent after two recrystallizations from acetone (120 cc. per gram of dye). The orange-red needles with a green reflex had melting point 223-224 C. with decomposition, and sensitized a photographic gelatinosilver-bromo-iodide emulsion to about 610 mu. with maximum sensitivity at about 580 mu.

Example 6.-3-ethyZ-5-[(3-methyl 2( 3) benz-.

oxazolylidene) ,B-(p chlorophenomy) ethylz'denelrhodam'ne 2.60 g. (1 mol.) of Z-(p-chlorophenoxymethyl) benzoxazole and 1.28 g. (1 mol.) of methyl sulfate were heated together at 105-110 C. for 37 hours. To the crude quaternary salt were added 3.06 g. (1 mol.) of -acetanilidomethylene-3-ethy1 rhodanine, 15 cc. of dry pyridine and 1.01 .g. (1 mol.) of triethylamine. This reaction mixture was heated at the refluxing temperature for 25 min-- utes. The cool mixture was stirred with 200 cc. of ether and after chilling at 0 C. the solids were collected on a filter and washed with ether. The residue was stirred, in a beaker, with cc. of hot ethyl alcohol and after chilling the suspension at 0 C., the solid was washed on a filter with ethyl alcohol. The dye was recrystallized twice from acetone (110 cc. per gram of dye) and obtained in a 6 per cent yield. The light red crystals with a blue reflex had melting point 283-284 C. with decomposition, and sensitized a photographic gelatino-silver bromo iodide emulsion to about 610 mu. with maximum sensitivity at about 575 mu.

2.60 g. (1 mol.) of 5-chloro-2-phenoxymethylbenzoxazole and 1.26 g. (1 mol.) of methyl sulfate I were heated together at 105-110 C. for 37 hours. To the crude quaternary salt were added 2.90 g. (1 mol.) of 5-acetanilidomethylene-3-ethyl-2- thio-2,4(3,5) -oxazoledione, cc. of pyridine and 1.01 g. (1 mol.) of triethylamine. This reaction mixture was heated at the refluxing temperature for minutes. The cool reaction mixture was stirred with 150 cc. of ether and after chilling at 0 C., the solid was washed on a funnel with ether. The residue was stirred, in a beaker, with 10 cc. of hot ethyl alcohol and after chilling the suspension at 0 C., the product was washed on a funnel with ethyl alcohol. The yield of dye was 16 per cent crude and 9 per cent after two recrystallizations from acetone (325 cc. per gram of dye). The minute light orange crystals had melting point 291-292 C. with decomposition, and sensitized a photographic gelatino-silverbromo-iodide emulsion to about 560 mu.

Example 7a.-5-[3-ethyl-2(3) benzothz'azolylidene) --fl-methoxyethylidenel 3-phenylrhoclanine 1.79 g. (1 mol.) of Z-methoxymethylbenzothiazole and 1.54 g. (1 mol.) of ethyl sulfate were heated together at the temperature of the stream 60 bath for about 3 days. To the resulting crude quaternary salt were added 3.54 g. (1 mol.) of 5- acetanilidomethylene-3-phenylrhodanine, cc. of ethyl alcohol and 1.06 g. (1 mol.-+5% excess) of triethylamine. The reaction mixture was 65 heated at the refluxing temperature for 30 minutes. After chilling at 0 C'., the solid was collected on the filter and washed with methyl alcohol. The residue was stirred, in a beaker, with acetone and filtered. The yield of crude dye was 1.0 g. (23% of the theory). The dye was purified by stirring it with 45 cc. of boiling acetic acid and filtering hot. The undissolved portion was recrystallized from 145 cc. of acetic acid. After another recrystallization from acetic acid, the yield of dye was 8 per cent. The green crystals had melting point 28-3-285 C. with decomposition. The dye sensitized a photographic gelatinosilver-bromiodide emulsion to about 640 mu. with maximum sensitivity at about 540 and 600 mu., the former being the stronger.

The cyclammonium quaternary salts containing, in the oi-position, an alkoxymethyl group or an aryloxymethyl group are prepared as shown in the foregoing examples, by adding an alkyl [5 salt to heterocyclic bases containing an alkoxy 1 methyl or an aryloxymethylgroupdn the a-POSition.. The following examples will serve to illustrate the preparation of these heterocyclic bases.

Example 8.-2 (p Methoxyphenoasymethyh- I bcnzoazazole r 40.3 g. of 2-(pmethoxyphenoxyacetylamino)- phenol and 13 g. of phosphorus pentoxide were intimately mixed and the mixture was heated at 17.0" C. for 30 minutes. The liquid portion was poured, with stirring, sin-to 800 :cc. of. l3lper cent aqueous sodium carbonate and the residue remaining in the reaction flask was treated with 200 cc. of hot'3- per :cent aqueous sodium carbonate; Both portions were combined .and thoroughly-extracted with ether. The ether layer was collected and washed with .water. After distilling oi? the ether, the residue distilled-"at 182 -190 C. at 2mm. The product was poured into a small volume :of methyl alcohol. After chilling, the crystals were washed on the funnel with methyl alcohol. The yield of colorless crystals was 46 per cent and they had melting point 4850 C.

"The 2 ('p methoxyphenoxyacetylamino)- phenol was prepared as follows:

Y 15.1 g. -(1 mol.) of o-aminophenol was dissolved in 50 cc. of pyridine and 27.8 g. (1 mol) of p-methoxyphenoxyacetyl chloride was added slowly, with shaking, and. then the mixture was 7 heated at the temperature of the steam bath for 20 minutes. The mixture was poured, with stirring, into a solution of 20 g. of sodium carbonate dissolved in about 2 liters of Water. The product separated as a sticky mass( The aqueous layer was decanted and the residue washed with water. It was dissolved in alcohol and precipitated by the addition of water. The product remained sticky. It was air dried and used without further purification.

The p-methoxyphenoxyacetyl chloride employed above was prepared as follows:

A mixture of 59.2 g. (1 mol.) of .p-methoxyphenoxy acetic acid and 7116 g. -(2 mols.) of thionyl chloride was heated in a water bath having a temperature of 70-JZ5 C. for 2 hours. The mixture was distilled and the 'fracti'o'n distilling at 145-152 C. at .15 .mm. was collected as the acid chloride. Yield 94 per cent.

In a similar manner, 2 phenoxymethyl- 5- phenylbenzoxazole was prepared as colorless crystals melting at 91-92 C. Also in a similar manner, 5-chloro-2-phenoxymethyl benzoxazole was prepared as colorless crystals melting at 85-88 C., 2 (p 'chlorophenoxymethyl) benz-.

oxazole was prepared as colorless crystals melt- Example 9.-2rethomymeifhylbeneoxazole G-GHzOGaHr .24 g. of. ethoxyacetylaminophenol and 9 g. of phosphorus pen-toxide were intimately mixed and the mixture wasrheated at C. for 30 minutes. The reaction mixture was :poured {into 1 liter-of 3'lper icent aqueous sodium carbonate and the base extracted with ether. The ether layer was collected and washed with'water. After distilling on the ether, the residue "was distilled, and the distillate redistilled at *1-'32 C. at 20 mm. The yield of clear liquid was 23 per cent The 2-ethoxyacetylaminophenol was prepared as follows:

21.8 g. (1 mol.).of o-aminophenol was dissolved in 50 cc. of pyridine and 24.5 g. (1 mol.) of ethoxyacetyl chloride was added slowly, with shaking, and then the reaction mixture was heated at the temperature of the steam bath for 20 minutes. The mixture was poured, with stirring, intoa solution of-20 g. of sodium carbonate dissolved: in about 2 liters of water. The colorless crystals were washed, on the funnel, with cold water and the yield was 64-per cent.

Example 10.- m-To'loauymethylbenzothiazole A solution of 55.2 g. (2 mols.) of m-toloxyacetyl chloride in. 100 cc. of dry benzene was added over a period-of 2 minutes to a suspension of 47' g. 1 mol.) of zinc o-aminophenylmercaptideand 11 g. of zinc. chloride in 350 cc. of dry benzene with mechanical stirring. After 15 min? utes at room temperature, the mixture was heated at the refluxing temperature for 15 minutes and filtered hot. The benzene filtrate was washed in a separatory funnel, with 50.0 cc. of about 11 per cent sodium hydroxide and then three times with Water. The residue obtained from filteringthe reaction mixture was stirred, in a beaker, with 500 cc. of about 1''? percent sodium hydroxide and 300 cc. of benzene. After filtering, by gravity, the benzene layer was collected and. washed with water. The benzene extracts were combined, dried over. potassium carbonate, and the filtrate distilled. The fraction, which distilled at 193-210 C. at 3 mm. was poured into ligroin (boiling point 6090 C.) and after chilling, the colorless crystals were washed on the funnel with ligroin. They had melting point 83-85 C. The yield of base was 52 per cent crude and 32 per cent after the ligroin recrystallization.

' In a similar manner, 2-ethoxymethylbenzothiazole boiling at 1 12 447 C. at 10mm. of mercury pressure was prepared, 2-( 3-naphthoxymethyl) -benzothiazole was prepared, p-chlorophenoxymethyl-benzothiazole boilingat 225"- 235C. at 3 mm. of mercury pressure and melting at 83 85 C. wasprepared, Z-phenoxymethylbenzothiazole was prepared and '2-phenoxymethylbenzoselenazole melting at 100-105? C. was prepared. I

- :Ji'scannplc 11 .92-phenoxy1nethyt-c-naphtho- 55.4 g. of phenoxyacetylecmaphthylamine and 50 cc. of dry pyridine were heated together, in an oil bath having a temperature of 115-120 C. To this hot solution was added slowly 22 g. of phosphorus pentasulfide with mechanical stirring and the mixture was heated for about 15 minutes. After pouring the reaction mixture onto cracked ice an excess of acetic acid was added. The phenoxythioacetyl-fl-naphthylamine, which separated was collected on a funnel. It was redissolved in an excess of dilute sodium hydroxide. The solution was filtered and to the filtrate was added some cracked ice and then an excess of acetic acid. Again the phenoxythioacetyl-fi-naphthylamine, which separated was collected on a funnel. It was redissolved in an excess of dilute sodium hydroxide, cracked ice added and oxidized to the desired base by the addition of aqueous potassium ferricyanide until the mixture was permanently yellow. The base was removed by extraction with ether. The ether layer was washed with water and then it was dried over potassium carbonate. After filtering, the filtrate was concentrated and the residue recrystallized from ligroin (boiling-point 90-120 C.). Thealmost colorless crystals had melting point 118-120 C.

Example 12.-2-1Jhenoxymethyl-p-naphthothiaeole 55.4 g. of phenoxyacetyl-a-naphthylamine and 250 cc. of dry benzene were heated to the refluxing temperature with mechanical stirring and 22 g. of phosphorus pentasulfidewas added slowly and heating was continued for 20 minutes. The hot benzene layer was poured onto an equal volume of cracked ice and an excess of sodium hydroxide was added. The aqueous alkaline layer was isolated and made acid with acetic acid. The phenoxythioacetyl-a-naphthylamine, which separated was collected on a funnel and redissolved in an excess of warm dilute sodium hydroxide. After filtering the solution, to the filtrate was added some cracked ice and then an excess of acetic acid. Again the phenoxythioacetyl-a-naphthylamine, which separated was collected on a funnel. It was redissolved in an excess of dilute sodium hydroxide, and oxidized to the desired base by the addition of aqueous potassium ferricyanide to theice cold mixture until it was permanently yellow. The base was removed by extraction with ether. The ether layer was washed with water and then it was dried over potassium carbonate. After filtering, the filtrate was concentrated and the residue twice recrystallized from methyl alcohol. The almost colorless crystals had melting point 116-118 C.

The phenoxyacetyl-m-naphthylamine and phenoxyacetyl-p-naphthylamine employed in Examples 12 and 11 were prepared as follows:

43 g. (1 mol.) of u-naphthylamine and 51 g. (1 mol.) of phenoxyacetyl chloride were mixed together. After the vigorous reaction had subsided the mixture was heated on the steam bath for 15 minutes. The product was removed from the flask, crushed and-washed on the funnel with water and then it was recrystallized from methyl alcohol. The colorless crystals were obtained in an 80 per cent yield and they had melt- The cyclammonium quaternary salts containing, in the a-position to the quaternary nitrogen atom, a e-arylamino-a-alkoxyor aryloxyvinyl group can be prepared by condensing a cyclamon a funnel and washed with acetone.

- acetone.

75distributed throughout the emulsions.

" acetone and after chilling the suspension at 0 C monium quaternary salt containing an alkoxymethyl or aryloxymethyl group with a diarylformamidine, in the presence of an anhydride of a carboxylic acid. The following example will serve to illustrate the preparation of such cyclammonium quaternary salts.

benzothiazole methz'odide 4.7 g. (1 mol.) of 2-phenoxymethylbenzothiazole methiodide, prepared by heating the base and methyl iodide together at the refluxing temperature for 12 hours, and 2.42 g. (1 mol.) of diphenylformamidine were heated together in 10 cc. of acetic anhydride at the refluxing temperature for 17 minutes. The dark brown mixture was chilled overnight at 0 0., and the crystals were collected The residue was stirred, in a beaker, with 20 cc. of Warm the brown product was washed on the funnel with It was used without further purification.

' We have found that our new dyes spectrally sensitize photographic silver halide emulsions when incorporated therein. The dyes are especially useful for extending the spectral sensitivity of the customarily employed gelatino-silverchloride, gelatino-silver-chlorobromide, gelatinosilver-bromide and gelatino-silver-bromiodide developing-out emulsions. In the foregoing examples, the extent to which gelatino-silver-bromiodide developing-out emulsions can be sensitized as well as the point of maximum sensitivity are pointed out in connection with the dye of each example. To prepare emulsions sensitized with one or more of our new dyes, it is only necessary to disperse the dye or dyes in the emulsions. The methods of incorporating dyes in emulsions are simple and are known to those skilled in the art. In practice, it is convenient to add the dyes to the emulsions in the form of a solution in an appropriate solvent. Methanol or acetone has proved satisfactory as a solvent for most of our new dyes. Where the dyes are quite insoluble in methyl alcohol, a mixture of acetone and pyridine is advantageously employed as a solvent. The dyes are advantageously incorporated in the finished, washed emulsions and should be uniformly QAQQQM.

. T QQ GIltI@12iQp; 9 the dyes in theemulsions canvary widely, e. g.f rom 5 t 100 mg. per liter of flowable emulsion. The concentration of the dyes will vary according'to the type of emulsion and accordingtothe efiect-desired. The suitable and most economical concentration for any given emulsion willlbe aparent to those skilled in the art, making the ordinarytests and observations customarily used in the art of emulsion making. Toprepare a elatino-fiilver-halide emulsion sensitized. with one or. more. ofour new dyes, the following procedure is satisfactory A quantityof. dye is dissolved in methyl alcohol or, acetone (or amixtureof acetone and pyridine) and. a volume of this solution, which may be dilutedwith water,, containing from 5 to 100 mg. of. dyei is slowly added to. about 1000 cc. of gelatinoesilver-halide emulsion, with, stirring. Stirring is continued until thedye. is thoroughly dispersedrin. the emulsion.

' Withmestofour from 10 to mg. of dye per liter of gelatino-silver brornide or. bromiodide emulsion (containing about g. of silver halide) sufiicesto produce the maximum sensitizing effect. With the finengrain emulsions, somewhat larger concentration of dye may be needed to produce the maximumsensitizing effect.

The above statementsaneonly illustrative, as it will be apparent that the dyes can be incorporated in photographic emulsions by any of the other methods customarily employed in the art, e. g. by bathing a plate.or film upon which an emulsion is coated in a solution of the dye in an appropriate solvent. However, bathing methods are ordinarily notto. epreferred. Emulsions sensitizedwith the; dyescan'be coatedon suitable supports, such as glass, cellulosederivative film, resin film; o jnape in he su m ne What we claim. asour invention and desire to be seeurcdf'hy Letters Patent of the United State s;

l. The dimethinemerocyanine; dyes of the following enerallfq m l i ,{ZAX Q31 I/Q\ R 1 -b=t o11=c-c=o ere n i re e n s an. a kyle oup f e for.-' mula Cal-12ml wherein n represents a positive; integer, R1 represents a member selected from t e group onsisti oi a kyl roups. a yl, r ups of the benzene series and aryl groups of the. aphthal n series. renresentsthe. non-metallic. atoms. necessary: to complete, a heterocyclic, nucleus selected from. the group consisting. of those of the henzo azole series, those of the. benzothiazole series, those of the, benZOselenazole-v ric r hos he r-naphtho az le s ries. th se of. the pj.-na hthoxazole' eries, those of the. n nh h hiaznle s ries. and those f, the.- c-napht'hothiazole series. and. Q], represents the. non-metallic atoms necessary to complete a heterocyclic, nucleus, selected from the. group, consisting of, thQ Q'Of the rhodanineseries and thos o he 2-thio:2, ,5; roxazol d n series.

Zfiljhe dimethineni'erocyanine dyes. of the folow ng g n rali mula:

.2. QR1 ,Q\\ Rl-i'b=(E'-GH=-'b=0 wherein ,R represents analkyl. groupof the for.- mula .CnHzn wherein represents a positive.

teg Qfl om o Rirepr s n san aryl group. of the benzeneseries, represents the non-me tallic atoms nece s,ary;to. Qmplete a .heterocyclic' nucleus selected fro n the. gl01l1l consistingof wh rein h =esents l yl; gro p f. h o

mula CflH2n+l whe ein n represents a positive integer of. from 1 Rrrcpreeents an-ary-lgroup; of the hfinze ese 5. Z epresents. th mommatallicatoms ece co plete a ter vclie n l s o th -hen hiazole s ri nd Q epr rsen s h non me lo ime n ce ar to m.- nlet a. het ocy lio nucleus: 0 t 'rh d nine se es-- 131e methinem m ran eos of he o lowing general formula-g;

wherein R represents an alkyl group of the formula CnH21L+1 wherein n represents a positive integer of fronglitg g m represents an aryl group of the benzene series, Z"-r epresents the non-metallic atoms necessary to complete a; heterocyclic nucleus of the benzoxazole series and Q represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the rhodanine series.

5. The.dimethineimerecyaninedyes-ofthe-fol herein R rep e ntsant-arraignment the for. m le- Cohan .2 emesents. a. positive. DIEM-B0 2,111 remes ntsanarrlgroun: of; the. benzene seri Krehmfihtsith.e.nonamo i y-ito c mplete aheteroeyclio 9 3 fir blanzqxezo erseries: and: Q reprezesen t. e;.non?meta i9i a omsznecessary to. can. plete a heterocyclie nucleus or. the 2,-thio-..

2,4 (3 5 -oxazoledioneseries.

. 6., The dimethine:merqcyanimt d es or. the talow n mul s.

7. The dimethi'nemerocyanine dye of-the rol lowing f rmula;

9. A process for preparing a dimethine merocyanine dye comprising condensing, in the presence of a basic condensing agent, a cyclammonium quaternary salt selected from those consisting of those of the benzoxazole series, thoseof the benzothiazole series, those of the benzoselenazole series, those of the u-naphthoxazole series, those of the B-naphthoxazole series, those of the a-naphthothiazole series and those of the fi-naphthothiazole series containing in the a-position to the quaternary nitrogen atom a group selected from the group consisting of alkoxymethyl groups, aryloxymethyl groups of the benzene series and aryloxymethyl groups of the naphthalene series, with a heterocyclic compound selected from those represented by the following general formula:

wherein Ac represents an acyl group, R2 represents an aryl group and Q represents the nonmetallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of heterocyclic nuclei of the rhodanine series and heterocyclic nuclei of the 2-thio-2,4(3,5) -oxazoledione series.

10. A process for preparing a dimethine merocyanine dye comprising condensing, in the presence of a basic condensing agent, a cyclammonium quaternary salt selected from those consisting of those of the benzoxazole series, those of the benzothiazole series, those of the benzoselenazole series, those of the a-naphthoxazole series those of the p-naphthoxazole series, those of the u-naphthothiazole series and those of the p-naphthothiazole series containing in the a-position to the quaternary nitrogen atom a group selected from the group consisting of alkoxymethyl groups, aryloxymethyl groups of the henzene series and aryloxymethyl groups of the naphthalene series, with a heterocyclic compound selected from those represented by the following general formula:

OHSCO wherein Q represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of heterocyclic nuclei of the rhodanine series and heterocyclic nuclei of the 2-thio-2,4(3,5)-oxazoledione series.

11. A process for preparing a dimethine merocyanine dye comprising condensing, in the presence of a tertiary amine condensing agent, a cyclammonium quaternary salt selected from those consisting of those of the benzoxazole series, those of the benzothiazole series, those of the 14 benzoselen'azole series, those of the a-naphthoxazole series, those of the S-naphthoxazole series, those of the a-naphthothiazole series and those of the fi-naphthothiazole series containing in the a-position to the quaternary nitrogen atom a group selected gfrom the group consisting of alkoxymethyl groups, aryloxymethyl groups of the benzene series and aryloxymethyl'groups of the naphthalene series, with a heterocyclic compound selected from those represented by the following general formula:

wherein Q represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of heterocyclic nuclei of the rhodanine series and heterocyclic nuclei of the 2-thio-2,4(3,5)-oxazoledione series.

12. A process for preparing a dimethine merocyanine dye comprising condensing, in the presence of a tertiary amine condensing agent, a cyclammonium alkyl quaternary salt of the benzothiazole series in which the alkyl group is of the formula CnH2n+1 wherein n represents a positive integer of from 1 to 2, containing in the a-position an aryloxymethyl group of the benzene series with a heterocyclic compound selected from those represented by the following general formula:

wherein Q represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the rhodanine series.

14. A process for preparing a dimethine merocyanine dye comprising condensing, in the presence of a tertiary amine condensing agent, a cyclammonium alkyl quaternary salt of the benzoxazole series in which the alkyl group is of the formula CnH2n+1 wherein n represents a positive integer of from 1 to 2, containing in the a-position an aryloxymethyl group of the benzene series with a heterocyclic compound selected from those represented by the following general formula:

wherein Q represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the 2-thio-2,4 (3,5) -oxazoledione series.

15. A process for preparing a dimethine merocyanine dye comprising condensing, in the pres- 16. A: proeessffor preparing a; dimethinemerocyanin'e dye comprising condensing; inhthe pr esence' oflatertiary amine condensing 1 agent; 24m t'oloxymethyl)benzothiazole methomethylsulfat'e with fi aicetanilidomethylene 31- eth'yI -Zi-thio- 2513,5 -0xa,z01ed'ione-.

17. A process for preparing" a. dimethine' m'ero cyanine dye comprising condensing, in the presence of a tertiaryiamine, a2-.a,ryloxymethylbenzothiazole methomethylsulfate where the aryloxy group is of the benzene series, with S-acetanilidomethylene-3-ethyl rhodanine. v

LESLIE. Ce S BR'OQKER. FRANKVL. WHITE. s

16 REFERENCES-i CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,083,804 Zeh June 15, 1937 2,156,464 Schulz May 2, 1939 2,170,803 Brooker Aug. 29, 1939 2,170,804 Brooker Aug. 29, 1939 2,265,908 Kendall Dec. 9, 1941 FOREIGN PATENTS Number Country Date 466,097 Great Brita'in 1937 OTHER REFERENCES Beilstein, v01. 27*,page- 1-10, 3 ed. 

1. THE DIMETHINE MEROCYANINE DYES OF THE FOLLOWING GENERAL FORMULA: 